JP2827625B2 - Uninterruptible power system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an uninterruptible power supply, and more particularly to an uninterruptible power supply having a backup power supply and a diode connected between an output terminal and a ground.

[0002]

2. Description of the Related Art Conventionally, as this type of uninterruptible power supply,
The one shown in FIG. 3 is known. In the figure, a forward diode D1 is interposed between an input terminal 301 and an output terminal 302, and a backup power supply V1 and a forward diode D1 are connected between an output terminal 302 and the ground.
2 is interposed.

FIG. 4 is a diagram showing an operation state of the uninterruptible power supply in such a configuration. In the state T41,
The voltage V301 of the input terminal 301 is normal, and the voltage V302 of the output terminal 302 is equal to the voltage V30 of the input terminal 301.
It is a voltage (V301-Vf) obtained by subtracting the voltage drop Vf due to the diode D1 from 1.

[0004] In state T42, the input voltage V301 becomes "0" due to a power failure, and power is being supplied from the backup power supply V1 to the output terminal 302. The voltage V302 at the output terminal 302 is equal to the voltage of the backup power supply V1. The voltage (V303−Vf) is obtained by subtracting the voltage drop Vf due to the diode D2 from the voltage V303.

In the state T43, the power failure is restored, and the voltage V302 of the output terminal 302 is changed to the voltage V301 of the input terminal.
(V303−Vf) obtained by subtracting the voltage drop Vf caused by the diode D1 from (V303).

FIG. 5 is a circuit diagram of another conventional uninterruptible power supply. In FIG.
01 and the output terminal 502
1, a backup power supply V1, a forward diode D2, and a switch S1 are interposed between the output terminal 502 and the ground.

FIG. 6 is a diagram showing an operation state of the uninterruptible power supply in such a configuration. In the state T61,
The voltage V501 of the input terminal 501 is normal, and the voltage V502 of the output terminal 502 is a voltage (V5 obtained by subtracting the voltage drop Vf due to the diode D1 from the voltage V501 of the input terminal.
01-Vf).

In the state T62, when the input voltage V501 becomes "0" due to a power failure, the output terminal 50
The voltage V502 of No. 2 becomes “0” which is the same as the voltage V501 of the input terminal 501.

However, in the state T63, the switch S
1, the backup power supply V1 starts supplying power to the output terminal 502, and the voltage V502 at the output terminal 502 is a voltage (V50 obtained by subtracting the voltage drop Vf due to the diode D2 from the voltage V503 of the backup power supply V1.
3-Vf).

In the state T64, the power failure is restored, and the voltage V502 at the output terminal 502 is changed to the voltage V501 at the input terminal.
(V501-Vf) obtained by subtracting the voltage drop Vf due to the diode D1 from the above.

[0011]

The conventional uninterruptible power supply described above has the following problems. In the former case, since the voltage of the backup power supply is always close to the voltage applied to the input terminal, a small amount of current flows, and the capacity of the backup power supply decreases. On the other hand, in the latter case, although the above-mentioned problem is solved by turning off the switch in a normal state, power is not supplied to the load for a very short time from the power failure to the time when the switch is turned on. There was a problem that a power outage time would occur.

The present invention has been made in view of the above problems, and has as its object to provide an uninterruptible power supply capable of preventing a power failure from occurring while preventing a capacity of a backup power supply from decreasing. I do.

[0013]

In order to achieve the above object, according to the present invention, a first diode interposed between an input terminal and an output terminal and a high potential in a first backup power supply are provided. A backup power supply in which a second backup power supply is connected in series, a second diode interposed between the first backup power supply and an output terminal, and between the second backup power supply and an output terminal. A series circuit including an interposed third diode and a switch, and a switch control for turning off the switch when the voltage of the input terminal is normal and for turning on the switch when the voltage of the input terminal decreases. And a circuit.

[0014]

According to the first aspect of the present invention, when the power supplied to the input terminal is normal,
Since power is supplied from the input terminal to the output terminal via the first diode and the voltage of the input terminal is normal, the switch control circuit turns off the switch. At the moment when an abnormality occurs in the power supply of the input terminal, power is supplied from the first backup power supply to the output terminal via the second diode. After a short time, when the switch control circuit turns on the switch, the output voltage of the second backup power supply is higher than the output voltage of the first backup power supply because the first and second backup power supplies are connected in series. And power is supplied to the output terminal from the first and second backup power supplies via the third diode.

That is, by connecting the slightly lower first backup power supply to the output terminal, it is possible to prevent a minute current from flowing out of the first backup power supply and to output the minute current at the moment of a power failure at the input terminal side. A situation in which a power failure occurs in the terminal is prevented, and a predetermined voltage is secured by connecting a second backup power supply when a minute time has elapsed from the power failure.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram of an uninterruptible power supply according to one embodiment of the present invention. In the figure, a forward diode D1 is interposed between an input terminal 101 and an output terminal 102.

The backup power supply V is configured by connecting a second power supply V2 in series to the high potential side of the first power supply V1,
Here, a backup power supply V, a forward diode D2, and a switch S1 are interposed between the output terminal 102 and the ground, and between the output of the first power supply V1 in the backup power supply V and the output terminal 102. A forward diode D3 is interposed.

The switch S1 has a voltage detecting section for detecting the voltage of the input terminal 101. The switch S1 is turned off when the voltage is normal, and turned on when the voltage is abnormal (power failure). In the backup power supply V, the first power supply is slightly lower than the voltage applied to the input terminal 101, and substantially matches the voltage applied to the input terminal 101 with the second power supply connected in series. Like that.

Next, the operation of the present embodiment having the above configuration will be described. FIG. 2 is a diagram showing an operation state of the uninterruptible power supply in such a configuration. In the state T21, the voltage V101 of the input terminal 101 is normal and the output terminal 1
02 is a voltage (V101) obtained by subtracting the voltage drop Vf due to the diode D1 from the voltage V101 at the input terminal.
−Vf).

In the state T22, the input voltage V101 becomes "0" due to the power failure, and the power is supplied from the first power supply V1 to the output terminal 102. The voltage V102 of the output terminal 102 is the first power supply V102. V1 voltage V10
3 minus the voltage drop Vf due to the diode D3 (V103−Vf).

However, in the state T23, it is detected that the voltage of the input terminal 101 has become abnormal in the switch S1, the switch S1 is turned on, and the second power supply V2
Is applied to the output terminal 102, and the voltage V102 at the output terminal 102 becomes a voltage (V104-Vf) obtained by subtracting the voltage drop Vf due to the diode D2 from the voltage V103 of the backup power supply V.

In the state T24, immediately after the power failure is restored, the voltage V102 at the output terminal 102 is a voltage (V101-Vf) obtained by subtracting the voltage drop Vf due to the diode D1 from the voltage V101 at the input terminal.

In the state T25, a minute time elapses after the power failure is recovered, and the switch S1 determines that the voltage of the input terminal 101 has become normal, and the switch S1 is non-conductive.

[0024]

As described above, the present invention can provide an uninterruptible power supply capable of preventing a small current from flowing out of a backup power supply and preventing a power failure from occurring.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an uninterruptible power supply according to one embodiment of the present invention.

FIG. 2 is a diagram showing an operation state of the uninterruptible power supply.

FIG. 3 is a circuit diagram of a conventional uninterruptible power supply.

FIG. 4 is a diagram showing an operation state of a conventional uninterruptible power supply.

FIG. 5 is a circuit diagram of another conventional uninterruptible power supply.

FIG. 6 is a diagram showing an operation state of another conventional uninterruptible power supply.

[Explanation of symbols]

 101 input terminal 102 output terminal D1, D2, D3 diode S1 switch V backup power supply V1 first power supply V2 second power supply

Claims (1)

(57) [Claims] A first diode interposed between an input terminal and an output terminal; a backup power supply in which a second backup power supply is connected in series to a high potential side of the first backup power supply; A second diode interposed between the backup power supply and the output terminal; a series circuit including a third diode and a switch interposed between the second backup power supply and the output terminal; An uninterruptible power supply device comprising: a switch control circuit that turns off the switch when the voltage is normal and turns on the switch when the voltage of the input terminal decreases.